Japanese Laid-open Patent Publication No. 2000-121863 discloses a mechanical splice for placing distal end faces of two bare fibers end to end and connecting the bare fibers, and a coated optical fiber connection that uses the mechanical splice. A plurality of types of optical fibers having different coating diameters (fiber diameters) have recently been used. Consequently, in the technique disclosed in Japanese Laid-open Patent Publication No. 2000-121863, a mechanical splice for each diameter of optical fiber must be individually prepared as the optical fiber connector.